Agricultural apparatus



,r 15 TTORNEYS.

H. l. WASHBURN AGRICULTURAL AP ARATUS Nov. 6, 1928. 1,690,761

OriginaFL Filed July 10, 1926 9 Sheets-Sheet l IN V EN TOR:

' JikrbaztlWwkurzz, BY

Nov. 6, 1928. 1,690,761

- H. l. WASHBURN AGRI CULTURAL APPARATU 5 9 Sheets-Sheet 2 Original Filed July 10, 1926 IAN-g g v ,g v 51% WITI%S& J55 INVENTOR:

I 'Ha'beriflWaa kbmg H. l. WASHBURN AGRICULTURAL APPARATUS Nov. 6, 1928.

Original Filed July 10, 1926 9 Sheets-Sheet 5 I N VENTOR: ifemerflwaaizbzzrlg,

WITNESSES ,1 66 W Nov. 6, 1928. 1,690,761 H. l. WASHBURN AGRICULTURAL APPARATUS Original Filed Jul 10. 1926 9 Sheets-Sheet 19 FIG: r

yII/I/IIIIIII/IIIIIIIIIII mum r WITNESSES INVENTOR:

Hkrberi I. Vila-512112111;

[416G M BY ATTORNEYS.

Nov. 6, 192s.. 1,690,761 H. L WASHBURN v AGRICULTURAL APPARATUS OriginalFiled July 10, 1926 9 sheets-rsheet 5 i WWW TORNEYS.

WITNESSES Q L g 3 Q a g Q INVENTOI? Nov. 6, 1928; 1,690,761

H. 1. WASHBURN AGRICULTURAL APPARATUS Filed July 10. 1926 9 Sheets-Sheet v FIG XZY- Ori J27 INVENTOR: m mmm I. wasiw r WITNESSES I fl aw-46.40.. W

Nov. 6, 1928.

H. I. wAsHBuRN AGRICULTURAL APPARATUS FIG m INVENTOR- Herbert I- Wacshbw'n, By W TORNEYS.

Nov. 6, 1928. v 1,690,761

H. l. WASHBU RN AGRICULTURAL APPARATUS Original Filed July 10, 1926 9- Sheets-Sheet 9 i z 27 3 55 f j m FIG. m- E 1 E I All 251- 1.55 165 i i I F E E 1 Q WITNESSES J59; J41 INVENTOR:

3 Herbal LWqahburn 7 BY y 1' TTORNEYS.

Patented Nov. 6, 1928.

UNITED STA TBS PA'TE NT OFFICE.

AGRICULTURAL APPARATUS.

Applioation filedJ uly 10, 1926, Serial No. 121,514. Renewed March s. 1928 This invention relates to agricultural apparatus of the type shown and described in U. S. Letters Patent No. 1,087,620 granted to me under date of February 17,; 1914:, wherein the tool carrying tractor element (sometimes referred to as a syn-motor.) is independently movable and confined to circular or spiral travel about a fixed center post in plowing or cultivating. a field. I

In the main, my present invention is concerned with electrification of such agricuh tural apparatus, or in otherwords, toenable use of electric power in propelling the tractor element in lieu of the internal combustion motors heretofore employed for the purpose. In this connection, I also aim to provide automatic means capable of taking up (or letting out) upon the conductors carrying the electric current, (which may be either direct or alternating) from the field center post to the tractor element, concurrently with variation in the radius determining the spiral travel, and at the same time of compensatively regulatingthe tension of the conductors in accordance with variation in their spanthat is to sayto maintain said conductors just sufficiently taut at all times to prevent sagging without inducing harmful strains in them."

My invention is further concerned with means capable of being set to auton'iatically shut off the supply of current to the tractor element after a predtermined extent or period of travel thereof, 1. e., after "a predetermined areaof the field has been worked upon.

Other objects and attendant advantages of my invention will become readily apparent from the detaileddescription hereinafter oi": the typical. embodiment illustrated in the drawings. y

Fig. I is a plan View showing the"con1 plete apparatus set up in readiness for opeation. 1 I Fig. II is an elevation of the tether or field center post (with its appendages) about which the tractor element travels. e i I Fig. III is a side elevation of the tractor element on a larger. scale than in Fig. I.

Fig. IV is a rear view of the same." Fig. V shows a side view of the. main portion of the tractor element in. part section and in greater detail than depicted in F III. i

Fig. VI is a sectional view taken as indicalled by the arrows VI--VI in FigfV.

Fig. VII is a longitudinal sectional view of the reeling mechanisinfor theconductors carrying the electriccurrent from the tether post to thetractor elementrincidental to the travel ofthe latter. V e

F ig. VIII is a fragmentary detail sectional view taken locally'as indicated by the arrows VIII.V III in Fig. VII. Y

Fig. IX is a fragmentary longitudinal sectional view through one of the unitsof the spring motor employed t in connection With, the conductor reeling mechanism of Fi VII. I

ig. X is atraverse section taken as indicated by the arrows XX in; Fig.

Fig. XI is a detail plansectional view taken locally asindicated by the arrows XI -,XI.in Fig. VII. i

Fig. XII is a cross vsection view through the conductor reeling mechanism as viewed in the direction of the Fig.,VII.

Fig, XIII is a similar cross section taken as indicated by the arrows XIIIXIII in Ficr, ,VII. i I

ig. XIV is a perspective View of a spring element associated with a clutch forming part of the reeling mechanism.

XV is a perspective view of the anchorage bracket for the spring of F i XIV.

' 'FigfXVI is a fragmentary cross section taken locally as indicated by the arrows X VI-XVI in Fig. VII. J Fig. XVII is a fragmentary. sectional view taken as indicated by the arrows XVII XVII in Fig. XVI.

Fig. XVIII is a view taken as indicated by the arrows XVIIIXVIII'in Fig. XII showing the details of one ofthe electric contact brushes engaging the drum sections upon which the conductors are respectively wound. i

Fig..XIX is a fragmentary sectional view of automatic tension regulating means associated with the conductor reeling mechanism, the section being taken as indicated by the arrows XIX-FXIX in Fig. XIII.

Fig. XX is a fragmentary plan view of the tension regulating means aforesaid.

Fig. 'XXI is a detailsectional View taken as indicated by the arrows XXI XXI in Figs. XXII and XXIII are illustrations similar to Fig. XXI showing the partsin ditlerento erative positions. I Fig. XXIV a sectionai view taken as arrows XII XII in V indicated by the arrows XXIV.XXI-V in Fig. XX.

Flg. XXV is a view oi the reeling mecha-' nism tor the steering wvire by which the movements of the tractor element are guided, from the tether post, certain portions-being. broken away and shown in section in this illustration to better portray important details. i

"Fig; XXVI isfa staggered plan section I takenapproXimatelv as indicated by the Y els about the tether post.

Fig. XXIX is a detail section taken. lo-

callv as indicated bythe arrows in Fi XXV;

Fig. is a plan sectional view ofthe guide wire reeling mechanism taken in acoordance wlth'the'arrowsjXXXXXX 1n Fig. XXV.

tional viewftaken as indicated by the arrows XXXLLXXXI in FigIXXV,

F ig.-XXXII is a staggered section taken i locally as indicatedby the arrows vXXXII 'XXXIIinFig. XXXI.

I Figs. X'XXIII and XXXIV are respectively a. plan: vie-wand side elevationoi .a

snap switch for controlling the supplylbff electric power to. the tractor element. Figs] XXXV and'XX VI are respec an axial sectional view of tivelyjaf plan and the switch. V i V XXXVII is a detail sectional view taken as indicated by the arrows XXXVII '-XXXVII in' XXX III; and V I Fig. XXXVIII'is still anotherdetail sec tional view taken locally as indicated by the arrows XXXVIII XXXVIII.

In the complete assemblage of Fig. I,'my agricultural apparatus is shown ,as comprising'an independently movable tool-carrying tractor element 1- adapted to travel about a tether post 2, in the center of a field; under guidance of a'connecting steering Wire 3 see Fig; II also. Progression ofjthe tractor element l'is induced by rotation of its bull wheel 4 (Figs. III, IV and Vbthesame being housed in a guard casing '55 suitably secured to the frameiof said tractor eleg ment, and preferably equipped with pivoted spur padsor shoes 6'to insure efi'ective tractive engagement "with the ground. Curvi} linear travel of the't-ractor element'l is de termined through movement ot'a steering .oted: at .10 to the tractorfraine.

Fig. XXXI is a fragmentaryplan sec vwheel 7 'which is mounted on a fitting 8 ,pivotally'connec ted tothe outer end of a radius arm 9, the latter being in turn piv- A boom 11 projecting forward from the swivel fitting 8 of'the'steering Wheel 7 is connected,- 'bythe. guide or steering wire 3, with reeling mechanism 12 (to belater described detail) on' the tether post 2 wherebysa1d wire is gradually ta ken' up for let out) to determinespiral travel of the tractor elet in tangential relation to the prescribed curvature of travel of the tractor element 1 is predetermined automatically, by mecha nism partly indicated at 13in Fig. I. "This mechanism may besimila r in construction and operation tofthat disclosed in my Patent No. 1354,093' dated May 8, 1923., and need not therefore be further referred to herein,

. 0st 2 where connection is made to a ower line as will be ently; r r v I Thefmeans directly instrumental in propelling the bull Wheel 4: of the tractor ele ment 1 m" accordance-with present invention, includes an electric motor which is I niore fully explained presdiagrammatically shown by dotted outline 105 p "at 21 in This motor 21 isenclosed i in anappropriateprotective housing 22 on 23, 24with a starter box 25adapted to be ment I Proper tracking-of thebull wheel the tractor frame and connected by leads 21 serves to drive the pinion 27 of'a sprock- '(ful'crumed. on a. depending bracket 34 of thestarter box 25) andan interposed coupling link rod38, all as shown in Fig. V.

For the purpose of preventing premature shifting of the clutch collar 36 before the motor 2l has attained speed in starting, and

et chain connection 28 with a counter-shaft 29 that isjjour'n'alledina gear housing 80 I at the'side of the guard 5r A worm 31 on company withsimilar springs. oftheother units.76,; intending to rotatethe shaft 83 1 said'shafts 105 and 29. respectively.

in a clockwise direction, as consideredfin Fig. XII; Such-movement is communicated to the winding drum; -isubject' to compensative, regulationby means including a bevel differential 93 whereofthe gear 94 is integrally formed withthe 'head95 which closes the right hand endof the sleeve or shell (Fig. VII), while it, is keyed at 96 to the correspondingdrum; end spider; 53. The spring motor shaft 83is free to rotate in theaxial bearing boss97 of the head 95, and, beyond'said 'boss,flcarries the opposing bevel gear 98 of the differential. The common differential pinion 99 is mounted'qon a rotor 101 which is free on the shaft 83 and. formed with a spur gear that mesheswith a-pinion 102 on a short countershaft103 having bearing in the end frame 43, seeFigsQXIII, XIX. The counter-shaft 103'is rotated bywor-m gear 104 driven'by the worm, 104a which is fixed on one of.

the sections 105:, 1061 of a divided shaft journalled. in bearings 107 and 108 of the end. frame 43. The'shaft section 106 is constantly driven from the shaft 29, pre-.

viously mentioned (Fig. V),.through the medium of a transmission system embodyng a vertical shaft. 109 having bevel gear connections 110111 top and bottom with Couplingof the. shaftsections 105, 106 iseffected through shifting of a toothed c-lutchmember I '112 (Fig. XIII), splined on the first men-,

for differential action. haspivotal connection at the center with a tioned section 105, intoengagement with a corresponding clutch -member 113 on the second 106, by means ofayoke114 which is pivoted at 115, 115 to the end frame 43,'and whose arms 11 6 are notched. as at 117 in Fig. XI to taketheends ofbow springs 118. These springs 118 are joined by an integral crossconnection 119*(Fig; XIV). whereof theextended tongue 1 20. engagesthrough an opening 121 in a supplemental lateral bridging bracket 122 bolted .tothe frame43, while the shoulders 123 at each side of the said to'nguerest withinretaining cuts 124 aboveand below the bracket opening 121. The action of the bow springs 118, it will be seen, is such as to tend to maintain the clutch member 112eitherin. its active or inactive position. i

Functioning. ofthe clutch-yoke 114 is con trolled; by the compensating means detailedin Figs. XXXXIV.;- wl1ich,-a s shown, comprises alever 125 that has pivotal connection at opposite extremities with nuts 126. 127 engaging the oppositely threaded ends of the shafts 71, 83protruding -through the frame'43, the threads being ofvdifferent pitch The lever 125 also member 128 composed of; two partswhich slidingly engage between them a connecting rod'129 that extends to the clutchyoke 114, see Figs. VII-XI. Thisconnecting rod 129 has a winged key 129a'which is coextensive with the member 128 and normally wholly 132 spanned between their respectively op posite extremities.

Thus, when the lever 125 is moved to the left of its normal neutral positionas shown in Fig. XXIIIcon-U sequent upon the action of the screw thread 83b, the two-part member 128. in. responding to such movement, carries the'cross arm 130 withit; while the other cross arm 131 -is-restrained through contact of the contiguous end of the winged key 129a. The connect: ing rod' 129 is thereupon urged inward under reaction 'of the tension springs 132, and the clutch member 112 brought into-engagement-with its fellow 113. This is followed by rotation of the the shaft 83throughthe interposed worm gearing 104, 104m and the differential 93 in a manner obvious from Fig. VII, to w nd up the u n1ts;76 of the spring motor-75. Suchactionwill, obviously,con-

tinue until the normal reradjustmentis re; established in the parts'iof the reeling mechanisnr41 by reverse operation of the compensating means.

I The springmotor T 5 is initially wound up a by a handzcrank 135 at the outer end of the counter'shaft 103 which. carries the pinion 102,,seeFig. XIX, To do .this, however, it is first necessary to disconnect it from the previously described compensative mech-. anism' by which'itis cont-rolled, Accordingly, the worm gear 104 is loosely mounted in the counter-shaft 103 with capacity to run free (except fora certain amount of braking friction) i-upon withdrawal of a springpressed-cone-clutch collar, 136 by *means of a; hand wheel-137 having screw threaded engagement at 138withsaid shaft. I

The action of the winding drum 50 is snubbed by a brake band140 (Figs. VII,

XVI andXV II) embracing an integral an nular pulley-like GXtGDSlOILllI at the ri ht hand head 95 of the sleeve. or. shell 55. ne

7 endaof the brake band 140 is attached to a collar 142 on one of the tierodsi44, and the other to a lever 143 which is free on said tie rod. A coiled torsion spring 144,' influential upon the lever 143, normally maintains the brake band 140 in tension for maximum braking effect, By means of a handle 145,

the lever-143 may be turned in opposition to the spring 144 to slack the brake band 140 and render the. Winding drum 50 free for man-- ually' reeling in any remaining lengths of the conductors 19, 20 after. the tractor element-1 has completely traversed the field.

As shown in Fig. II thereelinginecha;

. freely about the upper reduced tubular end 2a of the latter. The parts of thisreeling mechanism 12 are protected in a box-like enclosure whereof the top section has the form of an integral casting or closure memher 151 (see Figs. XXV and XXVI) with the back closed by a removable sheet metal panel 152, while the lower section has back and side walls 153 of sheet metal and a bottom 154- suspended by tie rods 155, Fig. XXX, from the upper section 151, both sections being accessible through a hinged. door 156 at the front. The reeling mechanism 12 isentirelyremovable from the tether post 2 except for a hollow swivel fitting 157 which is supported about the upper portion 2a of said post by a ball thrust bearing 15,8, upward displacement thereof being-prevented by a collar 159 with a circumferential apron 160 surrounding a roller bearing 161 at the top to preclude access of water or moisture to the latter. The open side of the swivel fitting 157 is flanked by lateral flanges 162 to provide a sliding connect-ion for the enclosure Inember 151 as best shown in Fig. XXVI. \Vith this construction it will be apparent that the box-like enclosure 150, together with all its appurtenances, may be readily dislodged-simply by lifting itrelative to the swivel fitting 157-for removal from the tether post 2 andstorage" with the rest of the apparatus when not in use. A cover plate such as shown at 163 in F XXV II may, thereafter, be substituted to protect the parts within the hollow of the swivel fitting 157 from the weather. The winding drum 165 for the steering wire 3 is secured on a shaft 166 extending vertically through the lower section 153 of thebox like enclosure 150 and journalled in ball bearings 167, 168. The'guide or steering wire 3 enters the box-like enclosure 150 through a slot 17 0 formed between the swinging edge of the door 156 and the side wall, the slot being faced with felt 171 or other suitable absorbent material capable of retaining fluid lubricant for wiping said wire as it is spooled on the winding drum 165. The latter operationi effected with the aid of a spooling guide 172 which carries a grooved roller 173 for engaging thewire 3, and which isniovable up and down along a vertical rod 174 under-the influence of a feed screw 175 whereto rotative movement is imparted direct from the drum shaft 166 through the medium of a gear train shown at 176 in Figs. XXV, XXVI. The winding (lrun'i 165 derives motion as a result of bod.-

ily revolution ofthe reeling mechanism 12 around the tether post. 2. The parts instrumental in determining this include a spur pinion 177 on the drum shaft 166, and cooperative planetary gears178, 179 whereof the latter is fixed to the post 2 within the hollow of the swivel fitting 157. The spurpinion 177 issplined to the drum shaft .166 and is shiftable up and down into meshing engagement either with the planetary gear 178 aforementioned when the drum 165 ,to be rotated or with astationarytoothed plate 180 to lock said. drum against rotation when required or desired. As a means to enable such shifting of the spur pinionl177, I provide a clutch yoke 181that is pivoted at'182,

182 and hasa handlc183 which extends to the exterior through a slot in the sidewall of the enclosure 150. Blocks 1840f fiber-or the like having pivotal connectionwith the clevisarms of theyoke 161, engage inthe interval between the upper face of the spur pinion 177 anda disk 185-2150 spiined on the drumshaft 166. This disk 185 is maintained in frictional contact with the fiber blocks 184 by a compression spring 186 and thus prevents spinning of the winding drum 165 during unwinding of'the guide wire 3 (during initial setting. up of the apparatus) when the spur; pinion 177 is in the neutral position shown in the. drawings; For the purpose of temporarily maintaining the spur pinion 177 in the neutral position, I employ a pivoted hook 187 adapted to engage asupplemental arm 1880f the clutch yoke 181 as shown in Fig. XXXII. ,This hook 187 is tripableby upward thrust otthe rod 174 a ainst the action ofaspring 189 '(Fig. .1 XV), and' is accordingly provided with a finger 190 that projects intothe path ofa disk collar 200 on said rod. For convenience in shifting it as justexplained, the rod 174 extends downbeneath the enclosure'l50 WhGTQlt is equipped with. a knurled finger, knob 201. The portion of the tether post2 between the planetary gear,179.-and the upper rollei'bearing 161. of the swivel fitting 157, is

occupied bya pair of fixed collars 202, 203

,With medial sections 2045 of insulation wit-h iinbedded contact rings 205, 206 that have slight circumferential projection. shown in Figs; XXV and XX VHI. To; the fixed collars 205,206 are 'permancntv. connected the power leads 207, 208 that ex .id upward through the tubular portion 2afof the tether post 2, and emerge at the top where they are spliced into the power line wires 209, which, as depicted in Fig. II, are secured by suit-- able insulators 210, on a cross beam 211'. Current is taken from-the collector rings or fixed collars 205, 206 by brushes 212, 21.3 respectively set in holders 21 1 of insulation that span the openingv intothe swivel fitting 157 so as to be engageable by guide studs 215 let into the. casting 151. -Helical com pression springs216, surrounding the guide studs 215, serve to urge the brushes212, 213

into good. electric, contact with the ringsor 1 fixed collars 205, 206, andthe current thus taken'is conducted by leads 217,218 to a "twofpole snap switch 219secured to the opposite endwallof theenclosure 150 wlthin' the upper section 151 ofthe latter.

The switch 219 is fully detailed in Flgs.

XXXIII-XXXVIII and will be observed to comprise a rotor 220with wings 221, 222

adapted to bridge the gap between the opposing poleplates 223, 224, 225 and 226 that protruding extend through insulation 227 molded into opposite sides ot-the switch casing 228. The ends of thepole plate's 224 and 226 are accessible, through apertures of "an insiilatingbushing 229-inthe end wall of "the enclosure 150 (Fig. XXV), to enable connection of a plug 230 at'the end of leads 231 extending from the conductors 19, 20.

' As shown in' Fig. II, the inner ends of the conductors 19,20 are remo vab'ly attachedby a hook 233, to an upwardly rojectin bracket-arm 234 of the enclosure casing-151. Referring again to Fig. and also to Fig. XXVII, it will be noted that t-heac'tuating stem 235 ofthetwo pole snap switch 219 protrudes'through the top=ofthe casing 151 where-it is"provided with a finger lever 236 for manual operation. 'Snapaction of the two poleswitch 219 isdetermined by bow springs 237 238 (Figs. XXXIII,

, againstthe anchorage post's 242,-243for'the bow springs 237, 238 as the snap switch-219 XXXIV and XXXVI") alternately influential upon an oscillating member 239'fast'on the switchact-uating stem 235. This oscillating member 239 carries top and bottom rollers 240, 24 1, which fire'spectivelyfcome to rest is turne'd'toopen or closed position.

Forthe purpose of automatically controlling the twopole switch 219, I provide means as follows Splined-"to the'top of the feed screw 17 5 (Fig. with'capacity for independent axial shifting, shaft extension'245 whose upper end has guidance in a bea'ring boss 246 ontop of the enclosure castmg 151. Secured tothe shaft extension245, immediately beneath the bearing 246, is a'n elementf'247 having arms 248,249 indifferent vertical planes adapted to respectively engage the rollers 240, 241 on the oscillatable member 239 selectively, all in accordance witlrthe shifting of saidshaft extension and the direction of rotation of the screw 175- as more "fully explained "later.

edges of the arms 248,2490t element 247 The 1 leading are quite sharp as depicted atf-249ain Fig. XXXVII, and the rollers 240, 241 circumterentiallyfg'rooved to insure precisionof operation and definite selectivity as between the latter. Shifting of 'the shatt extension 245 is dependent uponautomatically-induced longitudinal movement of the vertical rod 174broughtabout, through engagement of collars 250, 251 thereon, Zby thev spooling guide 172+as the latter approaches thejilirnit of its travel in either direction, such inoveinent-beingtransmitted by a clevis arml'252 conductors are drawn" in by NVl11Cl111g drum 50.

on the rod (Fig; engaging a circ'um terential groove in theenlargement 253 at.

the lowerend ofth'e shatt extension 245. The collars 250, 251 are split as shown in Fig. XXIX so as to be fixable by clamp screws 254' in different adjusted positions along the rod 174, but are heldaligned against the possibility of independent rota tion through engagementof integral lugs 255 in a longitudinal groove'174a 'in said rod. Inadchtion to capacity for end on shifting, the rod 174-is rotatable in "opposition to the. torsion of the spring 189 soas to allow slight further 'reeling'ofthe s'pooling guide 172 '(as may berequired in' settingup or dismantl ng "the apparatus) along marginal portions at opposite ends otthe winding drum 165;:said spooling gu-ide172 being,

tothis end, cutaway topand'bottom as at 172a to clear th'e'lug's 2 55 onthe" stop collars 250, 251, An arm 256, pivoted for tree 'vertic'alnmvem'ent to ears 257 on the enclosure casting 151 has, at its outer end,"an e'ye258 through which the steering orguide wire/3 passes enroute to'the winding drum 165. By. engaging the steering orguide wire 3 at a distance in advanceof the winding drum 165,

the arm 25 6 "serves not only to steady said W1re,but at the same time obviates excessive lateral straEn thereon due to the drag of the reeling mechanism'41 as-it revolves about the tether post 2.

A bar 259 of insulation on the tractor element "1 (Figs. I and'V), prevents electric Contact of the conductors 19,20 with any'o'f the metallic parts. Spacers (which may be of b'amboo or other suitable insulating ma;

The use-fandoperation of my in'vention is as follows: The tractor element 1 is first placedin the desired position at the edge of thefieldto be operated upon, all'manoeuvering for this p urpose'being with the aidof the auxiliary internalc'ombustion engine 39 to propel said element, and bynia'nual guidance wit-lithe aido'f the steering Wheel 14.

When the foregoing has been accomplished,

the auxiliary motor or '-internal combustion. engine 39 is stopped, and the handle 40a (Fig V) thrown to unclutchthe same. The 'box l50enclosing the reeling mechanism 12 'isinext hung on the swivel fitting'157 of the.

tether post 2 and the handle" 183 (Fig. XXV) moved to the illustrated position so as to free the, winding drum and 1 thereby permit unreeling of the guide: or

steering wire 3, whereof the end is carriedout-an'dla id down temporarily within a few the insulating spacers 260 (Fig. I) properly allocated; and, when thishas been done, the hook connection ad acent the conductor ends is hooked to the bracket arm 234 of the reeling mechanism casing 150 (Fig. II),

and the plug 280- pushed into the insulating socket 229, Fig.-XXV. -Following this, the sprlng motor (IS-is wound up to the full extent by rotatioi'l' of the winding crank handle 135 (FigsV and XIX) tovplace the conduittors 19, 20 under themaxirnuin ten sion, and the hand Wheel 1 37 (FigpXIX) drawn up to clutch the worm gear 10. During unwinding of the conductors 19, 20 as above explained, it willbe apparent that the rotative movement incidentally imparted to the screw shaft 71 will cause the nut 126 on the threaded end 71a of thelatter to travel towardthe left to a position m (Fig. XX); while rotation otthe shaft 83 during winding is attended bytravel of the nut127 to the right to a position n on the threaded portion 83?)" ofthe said shaft 83. The operative then'p'roeeeds to further draw out the steering wire 3, and this is in due course attended by engaa ment of the spooling guide 172 (Fig. 'XXV) with the stop collar 250 and lifting ofthe the vertical rod 17 1. Such movement is in'rpartedthrough the clevis arm 252, to the shaft extension 245 and the element 2 17 whose arm 248 is thus raised into the pathof the bottom roller 2 11. Thereitore, with further rotation of thefeed screw 1'? 5, the arm 2 18 causes theoscillating member .139 to be tripped to close the circuit through the two pole'snap' switch 219.

Then, with continued pull 0a the steering wire 3 and incident to further liftlnp; ot the vertical rod 1%, the pivoted hook or catch 187 is tripped and-the spur pinion 177 freed to the action of the'compression spring 186' whereby it is shifted into mesh with the planetary gear 178. The reeling mocha nism 12'being thus setin readiness for automatic operation-,wthe steering wire Bisfinally made fast to the "boom ll of-the tractor element 1. g I

All being nowiprepared, thestartinghox control lever 26 is moved in thedirection of the arrow in F ig. V, and whenthe elcc trio motor 21 has attained speed, the handle 37 is elevated to clutch the drive gearingf28 for the bull wheel are said motor. In

cidental to the ensuing travel of the tractor,

element 1, a reducing spiral course will be determined fOFJl't by virtue of the gradual taking up of the guide or steering wire 3 under automatlc operation oi the reeling mechanism 12 as. the latter revolves about the tether post 2, in the manner previously I described; Concurrently, the conductors 19,

carriage 67, which, atthistime, is progres- I sively moving toward the right with reioronce toFigs. VII; and VIII. As the opcration proceeds, the nut 126 (Fi travels toward theright along the threaded end 71!; ot' the shaft 71, while the nut 12? simnls taneously travels toward" the left on the threaded'end 83b of the shaft- 83. But, on account of the slow travel ofv the nnt126 as compared to the rapid unwinding of the spring motor 75 and rapid oonntertravel of thenut 127, the lever 125is caused to. swing on its pivot connection with the nut 126, aforesaid. As a consequence, the two-- partmember 128 is shifted toward the left as in Fig. XXIII permitting the tension springs 132 to draw the connecting rod 129' inwardly with reference to Figs. VII and XI for the purpose of clutching theshaft sections 105, 106 together. totation' is, thereupon immediately imparted to; the shaft 83 (in'a reverse direction) to partiallyrewind the spring motor .75 through nred-iuni of the differential gearing 9a, 98 and 99. Such winding continues at a more rapid rate than unwinding until the nut 127 (Fig. XX) is advanced sufficiently.xtowardthe right to restore the lever 125 to the normal neutral position illustrated with the shaft sections-105, 105 unclutchcd and the windingdrum '50 released once more to the ac tion of thespring motor 75 unmodified. by such zrewindingw The operation vjust described is periodically 1 repeated;but with. each succeeding actuation, it will be seen that the return increments of the nut 12'? (toward the right) areprogrcssively reduced with .impartation of less revolutions to the spring shaft 83 at each rewinding and cor-o responding gradual. easement ot the tension on the conductors 19, 20 as the tractor elomentl approaches the tetherpost 2. With this arrangement, it istherefore possible to begin with an initial tension on the con ductors 19, 20,*say in the neighborhood of eighty pounds for a starting span of 372 feet, and to decrease the samelittle by. little to a minimum of ten pounds for an 18 ft. radius at the finish, so that unduesagging is prevented; at all times without excessive] strain. i a I p y ,With reference againto Fig. it will be apparent that as the guide or steering wire 3 is drawn in by thewinding drum 165. the spooling guide 172 is gradually moved downward along the vertical guide rod 174. underaction ofthe feed screw 175. hen the spooling guide rod 172 finally engages the collar 251 and thereby depresseszthe rod 174 in opposition to the spring 189, the shaft extension 245 is obliged to follow suit, bringing the arin 2&9 of element 247 (Figs'XXV,

-XXXIII, XXXIV' and XXXVID into the plane of the-upper roller 240. Then,- with continued rotation of the feed screw -17 5,

I the arm 249 Will engage the :roller 240 to automatically trip the two pole snap switch 219 and thus open the circuitto the electric motor 21 onj'the tractor element 1."

Having thus described my invention, I claim: I v R a 1. In agricultural,apparatus of the character described, an independently-movable electrically-propelled tractor element 'adapted to travelacurvilinear course under guidance of asteermgcableuuth reference to a fixed point in afield, and independentcom pensatively tensioned conductors to carry electric current to said tractor element from said fixed point. a a a 2. In agriculturalapparatus of the character described, an independently-movable tractor element automatically operated by a single'electric motor and adapted'totravel about a fixed point in a field, independent spirally under guidance of a steering cable conductors to carry electric current to said tractor element from sa d fixed point, and

automatic 'means to compensatively 'reelthe conductors.

to a fixed point ina field, conductors to carry 8. In agricultural apparatus otthe character described, an independently-movable tractor element automatically operated by a single electric motor and adapted: to travel spirally inward under guidance of'a steering cable With. reference to a fiXed pointin-a field, independent conductors to carry electric'current'tosald tractor element. from said fixed point, and automat omeans operative to comp'ensatively reel in the conductors in cidental to decrease in'the TaClHIS'Of travel.

4-. In agricultural apparatuslofthe character described, an independently-movable electricallypropelled tractor elen'ient adapted to travel spirally inward with' reference electric current to said tractor element from said fixed po1nt, insulating spacers slidable on theconductors to normally malnt'am them separ ated, automatic mechanism" to WlIlCl in the conductors,'and'assoclated means to 1nci dentally detain and collect the spacers aforesaid; a

5. Ina'gricult-ural apparatus of'the-c-har-=i acter' described, an independently-movable electrically-propelled tractor element adapt-f ed to travel spirally about a fixed point in a field, 'conduc tors to carry electric current to said tractor e1ement-from said *fiXed point, slidableinsulating spacers normally maintaining the conductors separated, automatic fmechanism including a drum to reel the conductors, and associated means to incidentally detain the spacers-forcollection bef fore the drum; v

6. t In agricultural apparatus of the char-- acter described, an "independentlymovable electrically propelled tractor element adaptedto travel spirally about'a fixed point in afield, conductors tocarry electric current to the said tractor element from; the fixed point, 1 and automatic means for maintaining varying tension onsaid conductors proportionate to changes in their'spa'n.

" 7. In agricultural apparatus of the charelectrically-propelled tractor element adapted 'to travel aspiral coursewitlrreference to a fixed point in a field, conductors to'carry electric current to said tractor element from said fixed point, and automatic mechanism to incidentallyreel the conductors including a'drum, asp'rin'g motor to rotate the drum,

driving of the drum "by, the spring motor,

acter described, an. independently-movable and interposed differential -means enabling andperiodicrewinding of saidspring motor. 1

8. Inagricultural apparatusofthe character described, an independently-movable electrically-propelled tractor element adapted to travel spirallyabout afiXed point in a field, conductors'to carry icurrent to said tractor element from said fixed point, and automatic mechanism to incidentally reel the conductors includin'gja drum, a spring motor to rotate the'dru-m, and associated automatic means to' periodically rewind the a spring motor. a v I v 9. Inagricultural apparatus offthe character described, an independently-movable electrically-propelled tractor element'adapt ed to travel spirally about afiXed point in afield, conductors to carry current to said, I

' tractor element from said fixed point, and,

automatic mechanism to incidentally reel the conductorsincluding a drum, a spring motor to rotate the drum, and associated automatic means for periodically re'winding the motor tolinaintain varyingtension on: said conductors proportionate to changesin their span. p

10. In agricultural fapparatusot' the character described, an independently-movable electrically-propelled tractor 'element 'adapt ed to travel spirally abouta fixedvpointin a field, conductors to carrycurrent to said i acter' described, an independently-'movable electrically-propelled tractor element adapted to travel'spirally about a fixed point in;

a field, conductors to carry current to said tractor element from said fixed point, and automatic mechanism to incidentally reel the conductors including a drum, a spring motor to rotate the drum, a transmission coordinated with the drive of the tractor element, and differential means controlling automatic coupling with said transmission to periodically rewind the spring motor for maintenance of varying tension on said conductors proportionate to changes in their span.

12. In agricultural apparatus of the character described, an independently1novahle electricallypropelled tractor element adapted to travel a spiral course with reference to a fixed point in a field, conductors to carry electric current to said tractor element from said fixed point, and automatic means to incidentally reel said conductors including a drum with a spooling guide, a spring motor to rotate the drum, a transmission coordinated with the drive of the tractor element, a lever having pivotal connection with nuts travelling along differential threads respectively on the shafts of the spooling guide and the spring motor aforesaid, and a clutch controlled by said lever to effect periodic coupling of the transmission with the spring motor for partial rewinding to maintain varying tension on the conductors proportionate to changes in their span.

13. In agricultural apparatus of the character described, an independently-movable electric-motor-driven tractor element adapted to travel a spiral course under guidance of a steering cable with reference to a fixed point in a field, independent bare conductors to carry electric current to said tractor element from said fixed point, and

automatic gear driven reeling mechanism on the tractor element including a drum with separate insulated sections to respectively receive the conductors, and brushes bearing on said drum sections to take off the current for supply to the motor on said tractor element.

14. In agricultural apparatus of the character described, an independently-movable tractor element automatically operated by a single electric motor, means to guide travel of said element, and independent means to conduct electric current thereto from a fixed point in the field.

15. In agricultural apparatus of the character described, a tractor element automatically operated by a single electric motor and adapted to travel over a curvilinear course under guidance of a steering cable about a tether post in a field, independent conductors to carry current to the tractor element, collector rings fixed on said post, and brushes in circuit with the conductors aforesaid moving in contact with the collector rings.

16. In agricultural apparatus ofthe character described, an independently-movable tractor element automatically operated by a single electric motor, aguide wire with take up means to define spiral travel or the element about a fixed point in a field, independent conductors carrying electric current from said fixed point to the tractor element, and automatic means to compensatively take up on the conductors incidental to changes in. the span of the guide Wire aforesaid during the spiral travel of the element.

17. In agriculturalapparatus of the character described, an independently-movable tractor element automatically operated by a singleelectric motor, a steering cable to guide spiral travel of the tr ctor element, and a two pole snap switch to automatically cut off supply of electric current to the tractor element after a pre-determined period of travel.

18. In agricultural apparatus of the character described, an independently-movable electrically-propelled element, means to guide travel 01 the element, means to automatically cut oil supply of electric current to the element after a pre-determined period of travel, and means whereby the period of such travel may be varied.

19, In agricultural apparatus of the character described, an independently-movable electrically-propelled element, a guide wire with reeling means to defiine spiral travel of the element about a fixed point in a field, independent conductors to carry current to the propelled element, and means associated with the aforesaid reeling means to automatically cut off supply of electric current to the propelled element a'lter'a predetermined extent of spiral travel.

20. In agricultural apparatus of the character described, an independently-movable electrically-propelled tractor element and means defining spiral travel of the element about a fixed point in a field including a guide wire, a rotating drum to take up on the guide wire, means for spooling the wire on the drum, stops associated with said spooling means, and an electric switch subject to said. stops in automatically cutting off supply of electric current to the tractor element after a pre-determined extent of spiral travel. 7

21. In agricultural apparatus of the character described, an independently-movable electrically-propelled tractor element adapted to travel a curvilinear course about a fixed point in a field under control of a radial guide wire, reeling mechanism for said guidewire, independent conductors bearing current to the tractor element, a two pole snap switch in the electric circuit carrying current for actuation of said tractor element, and means to automatically close the switch aforesaid after a predetermined extent of unreeling of the guide wire incidental to initial arrangement of the apparatus.

22. In agricultural apparatus of the characteror described, an able electrically propel-led tractor element adapted to travel a spiral course about a fixed point in a field under control of a radial guide wire, mechanism to automatically reel said guide wire duringspiral travel of the tractor element, independent conductors bearing current to the tractorjelement, a two pole snap switch in the electric circuit carrying current for actuation of said tractor element, and means to close the switch aforesaid and to set the reeling apparatus for automatic operationafter a predetermined extent of unreeling of the guidewire incidental to initialarrangement of the apparatus. A 23. In agricultural apparatus of the char independently-inovactero described, an independentlyunorable electrically-propelled tract-or element adaptedto travel a spiral course about a fiexd point in a field under control of a radial guide wire, automatic mechanism, including Y a drum and driving connections to reel said guide wire during travel of the tractor element a switch in the electric circuit carrying current for actuation of the tractor element, and means to close the switch aforesaid and to clutch the reeling drum with its driving connections for automatic operationafter a predetermined extent of unreeling of the guide wire incidentally to initial arrangement of the apparatus. I

In testimony whereof, I have hereunto v.signedby name at Philadelphia, Pennsylvania, this second day of July, 1926.

HER-BERT I. WASHBURN. 

